1. Field of the Invention
The invention relates to a feed distribution and ladder chute system for use in silos or bins wherein granular fertilizer is fed and stored. The invention further relates to the application of conditioning agents, including dust control agents and anti-caking agents, to the granular material as it is being fed into the storage bin or silo.
2. Description of Related Art
Most storage practices for granular fertilizer involves the storage of fertilizer in piles. When dust control or anti-caking measures are taken, conditioning agents such as dust control and anti-caking agents, are applied and mixed with the pile.
In certain circumstances, it is desirable to store the granular fertilizer in holding bins or hopper type compartments such as a silo. In such circumstances, it is important that dust control measures be effectively applied to prevent caking, lower dust levels, and to effectively work the stored pile.
An objective or advantage of the present invention is to provide an apparatus which will enable the granular fertilizer to be evenly fed and distributed into the silo with a falling curtain type effect. Another advantage of this effect is that dust control or anti-caking agents can be applied effectively to the granular material as it is falling into the silo through the invention, thereby providing an efficient method of reducing dust levels within a silo while minimizing the caking of the granular fertilizer.
The present invention is a granular feed distribution and ladder chute apparatus for use within a silo. The apparatus includes a longitudinal vertically oriented ladder chute portion having four sides, a bottom end, and an upper end, the four sides forming a rectangular shaped chute, wherein two opposite sides are parallel to each other and wider than the corresponding shorter opposite and parallel sides.
The ladder chute portion has a plurality of flights or inwardly directed extensions. The flights are a predetermined width and each is fixed to one of two opposing internal sides of the ladder chute portion, preferably the wider sides of the ladder chute portion. Each flight further extends angularly from the wider side a predetermined length downwardly toward a center of the ladder chute.
For example, a typical application of the present invention may include a rectangular shaped ladder chute portion, where the ladder chute portion may have dimensions of about 36 inches on the wider sides and 18 inches on the shorter sides. The flights then would typically extend the full width inside the wider sides and the angular extension would typically be at about 45xc2x0 from the vertical wider side. The ladder chute portion and flights would typically be made from a material suitable to withstand the compressive pressures of granular fertilizer in a relatively tall silo, for example, 15 to 25 feet. In this application, xc2xc inch thick carbon steel may be used as a suitable construction material. In some circumstances, the use of non-corrosive materials such as Class 300 series stainless steels or corrosion resistant materials such as Class 400 series stainless steels may be preferred depending on the application. Of course, as stronger materials are developed, especially with non-corrosive materials such as fiber-reinforced polymers, these materials may also be considered for constructing the ladder chute portion with flights.
The flights are also staggered along the opposing opposite sides such that they alternate in a predetermined space-apart relationship.
Predetermined flights may optionally have cut-out portions or apertures from a section of the flight. Preferably, these cut-out portions or apertures are of a predetermined depth and width on a predetermined section of the flight, typically, a proximal side, a middle section, or a distal side. When such apertures are included in the invention, they are arranged in a predetermined alternating sequence on the plurality of flights wherein a distributed portion of the fed granular material can fall directly from a flight on one of the wider sides to another flight located on the same side of the one of the wider sides from which the granular material fell. These features further facilitate the mixing of the falling granular material, which has been previously coated with the dust control and anti-caking agents as hereinafter described.
Most hopper bins or silos have ladders or utilize other means for lowering personnel into the bin or silo. These means can be utilized to lower personnel inside a silo to inspect and clean out the flights. The clean out is done through a plurality of alternating access holes acting as means for access to the interior of the ladder chute. Each clean out or access hole is located on the wider sides substantially aligned opposite each flight inside the ladder chute portion. This alignment allows personnel to reach in and clean out and/or inspect the flight and the area around it.
The access holes further facilitate the spreading and distribution of the granular material or feed into the area in the silo around the ladder chute portion. As the granular material piles up inside the area encompassed by the ladder chute portion to an elevation level with an access hole, the granular material will begin to spill out into the surrounding area in the silo around the ladder chute portion to eventually fill the silo. Personnel can be lowered into the silo on top of the pile to inspect and/or clean out the ladder chute and flights through yet to be covered access holes.
Granular feed material is directed to the interior of the ladder chute portion at its upper end through a feeder chute or granular feed transition portion which is in cooperative engagement with the upper end of the ladder chute. Granular material is provided from a source into the transition portion, which is typically constructed from heavy duty sheet metal or plate sheets similar to a ventilation duct transition piece. The bottom section of the transition portion is preferably configured, although it need not be so configured, with an internally directed crowned section aligned with the approximate centerline of the transition portion such that when the granular material slides down over the bottom surface of the crowned section of the transition portion, the material spreads into a wider pattern thereby facilitating a more even distribution of the granular material into the ladder chute portion.
The end of the crowned section from which the granular material drops into the ladder chute may further have downwardly directed lip which provides additional structural support for the crowned portion to maintain its shape while the granular material is being fed over it.
In another embodiment of the transition portion, an extended portion of the bottom of the transition portion extends from the end of the crowned section a predetermined distance and width from the bottom of the lip portion of the crowned section or a predetermined distance and width from the end of the surface of the crowned section. This extended portion may optionally have a downwardly extending lip to further strengthen the configuration at the end of the extended portion from which the granular material falls into the ladder chute portion. The transition assembly or portion can be manufactured by numerous methods, including integrally welding each joint, riveting, sheet metal lap joints and other methods known in the art, keeping in mind that the gauge or thickness of the material chosen and the method of fabrication must be sufficient to maintain the configuration of the transition portion while the weight of the granular material is passing over its bottom surface.
In either embodiment of the feeder chute, the end from which the granular materials falls off the bottom surface into the ladder chute is preferably a width approximately equal to the interior width of the wider side of the ladder chute. This will enable an optimum spread and distribution of the granular material into the ladder chute. The angular orientation of the feeder chute with the ladder chute is such as to facilitate gravitational flow of the granular material into the ladder chute opening. For example, a typical angle between the centerline of the feeder chute or transition portion and the centerline extending downwardly into the ladder chute is preferably approximately 140xc2x0, although other slopes may be used.
Proximate the end of the upper end of the ladder chute, one or more nozzles are located on one, two, three or all 4 sides of the ladder chute. Each nozzle is installed and directed such that a predetermined spray pattern may be formed for spraying a concentration of dust control agent and/or anti-caking agent on the falling granular feed material. In this way the granular material may be coated with the agent at a sufficient concentration to control dust levels and/or to prevent caking of the granular material.
The falling material is tossed from one side of the ladder chute to the other side. This tossing is facilitated by the flights or slats. The notched flights serve to add a rolling effect to the granular material.